JP2009007429A - Pressure-sensitive adhesive composition and laminate using the pressure-sensitive adhesive composition - Google Patents

Abstract

[PROBLEMS] To provide a pressure-sensitive adhesive composition capable of forming an adhesive layer having good optical properties (transparency), heat resistance and moist heat resistance, good stress relaxation properties, refractive index controllability, removability, and the like. And provision of a laminate comprising the pressure-sensitive adhesive composition and an optical member.
A polyester having a weight average molecular weight of 30,000 to 300,000, which is obtained by polycondensation of a dicarboxylic acid component containing an aromatic dicarboxylic acid and a diol component containing a glycol having a hydrocarbon group in the side chain, and an aromatic dicarboxylic acid A weight obtained by polycondensing a dicarboxylic acid component containing an acid, a diol component containing a glycol having a hydrocarbon group in the side chain, and a trihydric or higher polyhydric alcohol and / or a trivalent or higher polyvalent carboxylic acid. A pressure-sensitive adhesive composition comprising a polyester having an average molecular weight of 3000 to 100,000.
[Selection figure] None

Description

  The present invention relates to a pressure-sensitive adhesive composition having excellent adhesion to various adherends, heat resistance, moist heat resistance and transparency, and more specifically, a pressure-sensitive type containing the polyester particularly suitable for laminating optical members. The present invention relates to an adhesive composition and a laminate using the same.

  Due to dramatic advances in electronics in recent years, various flat panel displays (FPD) such as liquid crystal display (LCD), plasma display (PDP), rear projection display (RPJ), EL display, light emitting diode display, etc. It has come to be used as a display device in various fields. For example, these FPDs are not only used indoors, including personal computer displays and liquid crystal televisions, but are also used in vehicles such as car navigation displays.

  A polarizing film and a retardation film are laminated on the liquid crystal cell member constituting the LCD. Also, these display devices use an antireflection film for preventing reflection from an external light source, a protective film (protection film) for preventing scratches on the surface of the display device, and the like. In addition to using the FPD as a display device, a touch panel function may be provided on the surface of the FPD to be used as an input device. A protective film, an antireflection film, an ITO vapor deposition resin film, and the like are also used for this touch panel.

  Various films used in the display device are used by being attached to an adherend with a pressure-sensitive adhesive. Since it is used for a display device, the pressure-sensitive adhesive is first required to be excellent in transparency. Therefore, a pressure-sensitive adhesive mainly composed of an acrylic resin is generally used.

  In recent years, suppression of interface reflection based on the difference in refractive index between the optical member and the adherend has been demanded from the viewpoint of effective use of light in the bonding process of the optical member. It is known to be advantageous to use a pressure sensitive adhesive layer having a refractive index that is intermediate to the refractive index of the adherend. Incidentally, if the refractive index difference at the interface is large, the incident angle causing total reflection becomes small, and the effective utilization of light is lowered.

  However, the refractive index of the adhesive layer using the conventional acrylic resin is around 1.46, whereas the refractive index of the material forming the optical member is, for example, around 1.52 for glass, methacrylic resin 1.51 for polycarbonate resin, 1.54 for polyethylene terephthalate (PET) resin, and there is a large difference in refractive index between them. When an optical member made of a resin, a polycarbonate resin, or a PET resin is bonded, the above intermediate refractive index cannot be obtained.

  Therefore, the acrylic pressure-sensitive adhesive for sticking the polarizing film to the glass member for a liquid crystal cell is required to suppress the dimensional change of the polarizing film itself and to further increase the refractive index of the adhesive layer. For this reason, by making the adhesive layer itself hard or increasing the adhesive strength, it is possible to suppress a relatively small dimensional change or a relatively short-term dimensional change. Further, the refractive index can be improved to some extent by using an aromatic ring-containing monomer, an aromatic compound, a compound containing a sulfur atom, or an inorganic compound.

  By the way, among the various films described above, the polarizing film has a three-layer structure in which both surfaces of a polyvinyl alcohol polarizer are sandwiched between triacetyl cellulose-based, cycloolefin-based, and polycarbonate-based protective films. Because of the characteristics of the materials that make up each layer, the polarizing film undergoes significant dimensional changes due to expansion and contraction due to heat and humidity. In particular, since the polyvinyl alcohol film constituting the polarizing film uses a stretched film, a force to return to an unstretched state due to heat or humidity may act after the polarizing film is attached to a glass substrate. Are known. This force is said to cause a dimensional change.

  With the recent increase in screen size of liquid crystal panels, the size of the polarizing film has also increased, and the amount of thermal deformation of the polarizing film has increased. When using a conventional pressure-sensitive adhesive, the stress at the time of sticking remaining in the adhesive layer is not sufficiently relaxed, so the adhesive layer cannot sufficiently follow the distortion of the polarizing film, resulting in a large liquid crystal When the panel is exposed to high temperature or high humidity, there is a problem that stress concentrates on the polarizing film and light leakage occurs in the large liquid crystal panel. This phenomenon is sometimes referred to as heat unevenness. On the other hand, if the stress relaxation of the pressure-sensitive adhesive is too strong, the adhesive force will decrease when exposed to high temperatures and high humidity, and the polarizing film will be displaced on the glass substrate surface or partially peeled off, resulting in a foamed state. Or Thermal unevenness, misalignment, and peeling are contradictory phenomena that when one of them is well designed, the other performance deteriorates. To satisfy both, it is necessary to balance the composition of the pressure-sensitive adhesive delicately. Required.

  Also, the polarizing film changes in dimensions while the liquid crystal panel is used over a long period of time, and the stress is accumulated in the adhesive layer. If stress continues to be accumulated in the adhesive layer, the distribution of the adhesive force between the polarizing film and the glass substrate for liquid crystal cell becomes non-uniform. During long-term use, stress concentrates particularly on the peripheral edge of the polarizing film, and as a result, the liquid crystal element surface is brighter or darker than the center. appear.

  In addition, after attaching a polarizing film to a glass substrate for a liquid crystal cell to make a laminate, in the inspection process, for things such as air or dust entrainment in the lamination process, peel the polarizing film from the glass substrate, There is a case where a new polarizing film is attached again (re-peeling). Pressure-sensitive adhesives are generally stored for a certain period of time at a high temperature to promote adhesion, and then inspected after that. After that, the adhesive strength becomes too high and it becomes difficult to peel off the polarizing film. In some cases, adhesive residue may be generated, resulting in insufficient removability.

  As described above, the pressure-sensitive adhesive used for laminating a polarizing film on a glass substrate for a liquid crystal cell has good optical properties (transparency), heat resistance and moist heat resistance, good stress relaxation, refraction. Controllability of the rate, removability, etc. are required. And the same performance is calculated | required also for the pressure sensitive adhesive for laminating | stacking the retardation film and the cover film of various displays.

  Conventionally, various pressure-sensitive adhesives have been proposed for these various requirements. For example, various pressure-sensitive adhesives based on acrylic resins are known (see Patent Documents 1 to 5). In addition, pressure-sensitive adhesives in which polyester or polyurethane is used in combination with acrylic resins are also known (see Patent Documents 6 to 9).

  By using an acrylic resin as a pressure-sensitive adhesive, foaming of the adhesive layer and lifting off from the liquid crystal cell of the polarizing plate can be suppressed, but stress due to dimensional change of the polarizing plate cannot be absorbed / relaxed, Since stress concentrates on the peripheral part of the polarizing plate, the brightness of the peripheral part and the central part of the liquid crystal display device are different, and there is a problem that uneven color and white spots are generated on the surface of the liquid crystal display device.

  In addition, pressure sensitive adhesives that use polyester and polyurethane in combination with acrylic resin are not compatible with acrylic resin and polyester or polyurethane, so long as a small amount of polyester or polyurethane is mixed with acrylic resin. Transparency is not significantly impaired, but if a large amount of polyester or polyurethane is mixed, the pressure-sensitive adhesive itself is whitened or separated. A pressure-sensitive adhesive for attaching a polarizing film or the like to a glass substrate for a liquid crystal cell requires extremely high transparency. And even if it tries to stick a polarizing film etc. to the glass substrate for liquid crystal cells using a pressure-sensitive adhesive with poor compatibility as mentioned above, phase separation and fluctuation will occur in the adhesive layer There was a point.

  By the way, because of good chemical resistance and workability, adhesives other than pressure-sensitive adhesives (hereinafter referred to as fiber coatings, paints, food packaging laminates and metal plates and plastic films) Polyester adhesives have been used in various technical fields such as adhesives). However, in the technical field of pressure-sensitive adhesives, it seems that polyester-based pressure-sensitive adhesives have been studied in the course of training, but practically they have not been studied. Occupied the majority.

  The pressure sensitive adhesive is used to form a pressure sensitive adhesive sheet. The basic laminate structure of the pressure-sensitive adhesive sheet is a sheet-like substrate / pressure-sensitive adhesive layer / single-sided pressure-sensitive adhesive sheet such as a release sheet, or a release sheet / pressure-sensitive adhesive layer / sheet-like substrate / pressure-sensitive type. It is a double-sided pressure-sensitive adhesive sheet such as an adhesive layer / release sheet. At the time of use, the release sheet is peeled off, and the pressure-sensitive adhesive layer is attached to the adherend. Pressure-sensitive adhesive is not only the pressure-sensitive adhesive layer has a tack at the moment when the pressure-sensitive adhesive layer touches the adherend during sticking, but it is completely different from the adhesive. It is necessary to have a cohesive force for maintaining the sticking state while having a tack and appropriate hardness without solidifying. The cohesive force greatly depends on the molecular weight. The higher the molecular weight, the stronger the cohesive force, and the lower the molecular weight, the lower the cohesive force.

  Since the acrylic resin is formed by addition polymerization, one having a molecular weight of several hundred thousand or more can be easily formed. On the other hand, since a polyester resin is formed by condensation, it is virtually impossible to form such a high molecular weight resin. In the case of a polyester resin, if the condensation and decomposition reach an equilibrium state, the molecular weight will no longer increase, and if the reaction conditions are changed and further condensation is attempted, it will compete with deterioration. It is. Therefore, in order to develop a high cohesive force while having tack, an acrylic resin having a relatively large molecular weight and easily exhibiting cohesive force is used as a main agent, and a relatively small amount of a curing agent is added to the main agent. It can be said that an acrylic pressure-sensitive adhesive that is easy to use and exhibits tack is suitable. On the other hand, a polyester resin having a relatively small molecular weight can be said to be suitable as an adhesive for firmly cross-linking with a relatively large amount of a curing agent to develop adhesive performance.

  In order to develop tack, it is necessary to use many aliphatic raw materials having flexible properties. In the case of an acrylic resin, the molecular weight can be several hundreds of thousands or more, so that even if a large amount of aliphatic raw material is used, heat resistance and heat-and-moisture resistance are imparted by this molecular weight effect. On the other hand, when a polyester resin having a relatively low molecular weight is used as a pressure-sensitive adhesive as compared with an acrylic resin, if a large amount of an aliphatic raw material is used, sufficient heat resistance and wet heat resistance cannot be obtained.

  Therefore, when a polyester resin is used as a pressure-sensitive adhesive, it is necessary to add a lot of crosslinkable functional groups to the polyester resin, and it is necessary to use a large amount of aromatic raw materials. Tend to decrease.

  However, there are various fields where pressure-sensitive adhesive sheets are used, and the level of requirements is increased, new requirements are added, and conventional acrylic pressure-sensitive adhesives are not fully meeting various requirements. Therefore, application of polyester resins to pressure-sensitive adhesives has been studied.

  For example, a polyester having a glass transition temperature (Tg) of −60 to 0 ° C. formed from a dicarboxylic acid component essential for dimer acid and a glycol component containing 30 mol% or more of a glycol having an alkyl group in the side chain is used. There is known a pressure-sensitive adhesive (see Patent Document 10). By using dimer acid as essential, it is presumed that tack can be imparted while using a considerable amount of aromatic dicarboxylic acid. However, since dimer acid is a component derived from a natural product, the quality varies greatly and the performance as a pressure-sensitive adhesive sheet tends to vary. In addition, when dimer acid is used, the polyester-based resin is colored. Therefore, it cannot be applied to the field where coloring is abolished, for example, optical applications and pressure-sensitive adhesives for constituting various display devices.

  Further, Patent Documents 11 and 12 disclose polyester-based resins containing a carbonate structure or a cyclohexane structure, but both of them have insufficient heat resistance and moist heat resistance (see Patent Documents 11 and 12).

  Furthermore, a pressure-sensitive adhesive comprising an acidic component containing an aromatic dicarboxylic acid, a diol component containing a glycol having a hydrocarbon group in the side chain, and a polyester comprising a trivalent or higher alcohol and / or carboxylic acid is known. (See Patent Document 13). The pressure-sensitive adhesive disclosed in Patent Document 13 is excellent in heat resistance and moist heat resistance targeted by the present invention, but has good optical properties (transparency), heat resistance and moist heat resistance, good stress relaxation properties, It does not satisfy all of the controllability of refractive index and removability.

  In particular, as described above, thermal unevenness, misalignment, and peeling are contradictory phenomena that, when one is designed well, the other performance deteriorates, and the polyester disclosed in Patent Document 13 satisfies both. I can't do that. Since the polyester resin has a relatively low molecular weight as compared with the acrylic resin, it is necessary to crosslink firmly in order to develop a high cohesive force. For this purpose, it is necessary to use a large amount of a crosslinking agent, but it is also necessary to contain many reactive functional groups in the polyester resin.

  In Patent Document 13, a polyester resin is synthesized by polycondensation of a dicarboxylic acid component and a diol component, a trivalent or higher polyhydric alcohol and / or a trivalent or higher polyvalent carboxylic acid. It is impossible to satisfy both the high molecular weight and the high functional group number that express high cohesion. That is, when a large amount of a trihydric or higher polyhydric alcohol and / or a trivalent or higher polyvalent carboxylic acid is used in an attempt to obtain a high functional group number, there is a problem that gelation occurs during the synthesis of the polyester. If the reaction is controlled so as not to gel, the resulting polyester becomes a low molecular weight resin, and a high cohesive force cannot be obtained.

It is generally considered that pressure-sensitive adhesives using these polyesters can improve the refractive index controllability, heat resistance and moist heat resistance, and good stress relaxation properties, which are disadvantages of acrylic resins. However, all of these cannot be satisfied, the initial adhesiveness (tack) is too low, or there is no cohesive force, and the function as a pressure-sensitive adhesive cannot be maintained. In addition, these have insufficient compatibility, and therefore, when applied to an optical film such as a polarizing film or a retardation film, phase separation, fluctuation, or protrusion occurs in the adhesive layer, and these are the starting points. As well as causing phenomena such as foaming and misalignment, not only the peel strength becomes too high after sticking, it is difficult to peel off the polarizing film etc. Is insufficient, it is not suitable for a pressure-sensitive adhesive for attaching an optical film such as a polarizing film or a retardation film.
Japanese Patent Laid-Open No. 01-066283 JP-A-10-279907 JP 2002-121521 A JP 2003-013029 A JP 2002-014225 A JP 2003-073646 A JP 2004-002827 A JP 2004-083648 A JP 2002-053835 A Japanese Patent Laid-Open No. 04-328186 JP 2002-194314 A JP 2004-99792 A JP 2007-099879 A

  The present invention relates to a pressure-sensitive adhesive used for laminating a polarizing film on a glass substrate for a liquid crystal cell, and has good optical properties (transparency), heat resistance and moist heat resistance, good stress relaxation properties, and refractive index. It aims at providing the pressure sensitive adhesive composition which can form the adhesive bond layer which has controllability, removability, etc. Furthermore, it aims at providing the laminated body which consists of this pressure-sensitive-type adhesive composition and an optical member.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention is obtained by polycondensing a dicarboxylic acid component (A) containing an aromatic dicarboxylic acid (a1) and a diol component (B) containing a glycol (b1) having a hydrocarbon group in the side chain. Polyester [I] having a weight average molecular weight of 30,000 to 300,000, and
A dicarboxylic acid component (A) containing an aromatic dicarboxylic acid (a1), a diol component (B) containing a glycol (b1) having a hydrocarbon group in the side chain, a trihydric or higher polyhydric alcohol (c1) and / or Or a polyester obtained by polycondensation with a trivalent or higher polyvalent carboxylic acid (c2), and a trivalent or higher polyhydric alcohol (c1) and / or a trivalent or higher polyvalent carboxylic acid (c2), 1 to 20 mol% of the total of the dicarboxylic acid component (A), the diol component (B), the trivalent or higher polyhydric alcohol (c1), and the trivalent or higher polyvalent carboxylic acid (c2) The present invention relates to a pressure-sensitive adhesive composition comprising polyester [II] having a weight average molecular weight of 3000 to 100,000.

  Furthermore, this invention relates to the said pressure sensitive adhesive composition containing the compound (D) which has a functional group which can react with the reactive functional group in polyester [I] and / or polyester [II].

  Furthermore, this invention relates to the said pressure sensitive adhesive composition whose compound (D) is a polyisocyanate compound.

  Furthermore, this invention relates to the said pressure sensitive adhesive composition characterized by including a silane coupling agent.

  Furthermore, this invention relates to the laminated body by which an optical member is laminated | stacked on the pressure sensitive adhesive layer formed from the said pressure sensitive adhesive composition.

  The present invention further relates to a liquid crystal cell member in which a glass member for a liquid crystal cell, a pressure sensitive adhesive layer formed from the pressure sensitive adhesive composition, and an optical member are sequentially laminated.

  The pressure-sensitive adhesive composition of the present invention can form an adhesive layer excellent in good optical properties (transparency), heat resistance and heat-and-moisture resistance, good stress relaxation properties, and refractive index controllability. In addition, by using the pressure-sensitive adhesive composition of the present invention, foaming or peeling occurs even under severer heat or wet heat conditions than before, particularly in optical member applications that require heat resistance and moist heat resistance. Without attaching the polarizing film to the glass substrate surface for the liquid crystal cell to make a laminate, the polarizing film is peeled off when the polarizing film is peeled off from the glass substrate surface and a new polarizing film is attached again. It has become possible to provide a laminate comprising an adhesive composition having good removability and an optical member, which is difficult or has no adhesive residue after peeling.

  The pressure-sensitive adhesive composition of the present invention includes linear polyester [I] having a weight average molecular weight of 30,000 to 300,000 and branched polyester [II] having a weight average molecular weight of 3000 to 100,000. To do. Linear polyester [I] contributes to adhesive strength and tack, and branched polyester [II] contributes to cohesive strength. The pressure-sensitive adhesive composition of the present invention can easily control these physical properties, and can be foamed even under severer heat or wet heat conditions than before, particularly in optical member applications that require heat resistance and heat and humidity resistance. Peeling or the like does not occur, stress concentration caused by expansion and contraction of the polarizing plate is alleviated, and color unevenness and white spots are not generated in the liquid crystal element.

  First, the linear polyester [I] of the present invention will be described. Polyester [I] is a polyester obtained by polycondensation of a dicarboxylic acid component (A) containing an aromatic dicarboxylic acid (a1) and a diol component (B) containing a glycol (b1) having a hydrocarbon group in the side chain. It is. Polyester [I] does not contain, as a constituent component, a trihydric or higher polyhydric alcohol (c1) and / or a trihydric or higher polyhydric carboxylic acid (c2) used in polyester [II] described later. That is, it is a straight chain, relatively high molecular weight polyester without branching.

  The use of the aromatic dicarboxylic acid (a1) improves the heat resistance and moist heat resistance, and when used for laminating optical members, problems such as film peeling and white spots do not occur. Moreover, a high refractive index is expressed. In this invention, it is preferable to use 10-80 mol% in an aromatic dicarboxylic acid type | system | group (a1) in a dicarboxylic acid component (A) as dicarboxylic acid component (A), and it is further using 20-70 mol%. preferable. When the amount of the aromatic dicarboxylic acid (a1) used is less than 10 mol%, the heat resistance and heat-and-moisture resistance are inferior, and when used for laminating optical members, problems such as film peeling and white spots may occur. Also, the refractive index may be low. Moreover, when it exceeds 80 mol%, adhesiveness falls and sufficient adhesive force may not be acquired.

Examples of the aromatic dicarboxylic acid (a1) of the present invention include phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m- Phenylene diglycolic acid, p-phenylene diglycolic acid, o-phenylene diglycolic acid, diphenylacetic acid, diphenyl-p, p′-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, Aromatic dicarboxylic acids such as naphthalene-2,6-dicarboxylic acid and anthracene dicarboxylic acid;
Aromatic dicarboxylic anhydrides such as phthalic anhydride, 1,8-naphthalenedicarboxylic anhydride, 2,3-naphthalenedicarboxylic anhydride and the like can be mentioned.

  In addition, the above aromatic dicarboxylic acid components and aromatic dicarboxylic acid anhydrides can be used as lower alcohols, for example, esterified products of alkyl alcohols having 1 to 4 carbon atoms. When an aromatic dicarboxylic acid component or an ester of a lower alcohol of an aromatic dicarboxylic acid anhydride is used, an ester bond is generated not by dehydration condensation with the diol component (B) but by an ester exchange reaction by dealcoholization. .

  Furthermore, a compound obtained by half-esterifying an aromatic tricarboxylic acid anhydride or an aromatic tetracarboxylic acid anhydride with a monoalcohol can be used as the aromatic dicarboxylic acid.

  Examples of the aromatic tricarboxylic acid anhydride include 1,2,3-benzenetricarboxylic acid anhydride, trimellitic acid anhydride, 1,2,4-naphthalene tricarboxylic acid anhydride, and 1,4,5-naphthalene tricarboxylic acid. Anhydride, 2,3,6-naphthalene tricarboxylic acid anhydride, 1,2,8-naphthalene tricarboxylic acid anhydride, 3,4,4′-benzophenone tricarboxylic acid anhydride, 3,4,4′-biphenyl ether tricarboxylic acid Acid anhydride, 3,4,4′-biphenyltricarboxylic acid anhydride, 2,3,2′-biphenyltricarboxylic acid anhydride, 3,4,4′-biphenylmethanetricarboxylic acid anhydride, 3,4,4 ′ -Biphenyl sulfone tricarboxylic acid anhydride etc. are mentioned.

Examples of the aromatic tetracarboxylic anhydride include pyromellitic anhydride, ethylene glycol ditrimellitic anhydride ester, propylene glycol ditrimellitic anhydride ester, butylene glycol ditrimellitic anhydride ester, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid anhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic acid anhydride, 1,4,5,8-naphthalene tetracarboxylic acid anhydride, 2,3,6 , 7-Naphthalenetetracarboxylic acid anhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic acid anhydride, 3,3 ′, 4,4′-dimethyldiphenylsilane tetracarboxylic acid anhydride, 3,3 ', 4,4'-tetraphenylsilanetetracarboxylic anhydride, 1,2,3,4-furantetracarboxylic anhydride, 4,4 '-Bis (3,4-dicarboxyphenoxy) diphenyl sulfide anhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone anhydride, 4,4'-bis (3,4-dicarboxy) Phenoxy) diphenylpropane anhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride, bis (phthalic acid) phenyl Phosphine oxide anhydride, p-phenylene-bis (triphenylphthalic acid) anhydride, m-phenylene-bis (triphenylphthalic acid) anhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether anhydride, Bis (triphenylphthalic acid) -4,4′-diphenylmethane anhydride, 9,9-bis (3,4-dicarboxyphenyl) fluorene Anhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic anhydride Products, 3,4-dicarboxy-1,2,3,4-tetrahydro-6-methyl-1-naphthalene succinic anhydride and the like.
Examples of the monoalcohol include methanol, ethanol, propanol, isopropanol, butanol, n-amyl alcohol, hexanol, heptanol, n-octanol, 2-ethylhexanol, isooctanol, nonanol, decanol, isoundecanol, lauryl alcohol, Linear or branched aliphatic alcohols such as cetyl alcohol and stearyl alcohol;
Araliphatic monoalcohols such as benzyl alcohol, α-methylbenzyl alcohol, phenethyl alcohol;
Examples include alicyclic monoalcohols such as cyclopentanol, cyclohexanol, cyclohexanemethanol, cycloheptanol, cyclooctanol, and tricyclodecane methanol.

  These aromatic dicarboxylic acid types (a1) can be used alone or in combination of two or more. Among these, terephthalic acid and isophthalic acid are preferable from the viewpoint of heat resistance and wet heat resistance.

Examples of the dicarboxylic acid component (A) other than the aromatic dicarboxylic acid (a1) include citraconic acid, malic acid, citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, Azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, fumaric acid, itaconic acid, maleic acid diglycolic acid, cyclohexane-3,5-diene-1,2-carboxylic acid, hexahydroterephthalic acid, Aliphatic and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid;
Succinic anhydride, maleic anhydride, glutaric anhydride, butyl succinic anhydride, hexyl succinic anhydride, octyl succinic anhydride, dodecyl succinic anhydride, butyl maleic anhydride, pentyl maleic anhydride, hexyl maleic acid Anhydride, octylmaleic acid anhydride, decylmaleic acid anhydride, dodecylmaleic acid anhydride, butylglutamic acid anhydride, hexylglutamic acid anhydride, heptylglutamic acid anhydride, octylglutamic acid anhydride, decylglutamic acid anhydride, dodecylglutamic acid anhydride , Methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylpentahydrophthalic anhydride, methyltrihydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methyl hymic anhydride, etc. Aliphatic, alicyclic dicarboxylic acid anhydride.

  In addition, polyester [I] has improved wettability to the substrate by using glycol (b1) having a hydrocarbon group in the side chain, and improved heat resistance and moist heat resistance. In this case, problems such as film peeling and white spots do not occur. In this invention, it is preferable to use 10-70 mol% of glycol (b1) which has a hydrocarbon group in a side chain as a diol component (B), and it is still more preferable to use 20-60 mol%. If the amount of glycol (b1) having a hydrocarbon group in the side chain is less than 10 mol%, the heat resistance and heat-and-moisture resistance are inferior, and problems such as film peeling and white spots occur when used for laminating optical members. There is a case. Moreover, when it exceeds 70 mol%, it exists in the tendency for a tack to fall, polymerization time becomes long, and a problem may be produced in productivity.

  The hydrocarbon group in glycol (b1) having a hydrocarbon group in the side chain is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 3 to 9 carbon atoms. preferable. Examples of the glycol (b1) having a hydrocarbon group in the side chain include neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2,2 -Diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4 -Diethyl-1,5-pentanediol, 1,3,5-trimethyl-1,3-pentanediol, 2-methyl-1,6-hexanediol, 2-butyl-2-methyl-1,3-propanediol 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-propyl-1,3-propanediol, 2,2-dibutyl-1,3-propanedio 2-pentyl-2-methyl-1,3-propanediol, 2-hexyl-2-methyl-1,3-propanediol, 2-hexyl-2-ethyl-1,3-propanediol, 2- Butyl-2-ethyl-1,4-butanediol, 2-butyl-2-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,6-hexanediol, 2-hexyl-3-methyl -1,4-butanediol, 2-butyl-2-ethyl-1,4-butanediol, 2-butyl-4-methyl-1,5-pentanediol, 2-propyl-4-ethyl-1,6- Hexanediol, 2-butyl-5-methyl-1,6-hexanediol, 2-hexyl-5-ethyl-1,6-hexanediol, 2,5-dibutyl-1,6-hexanediol, bisphenol Le A, hydrogenated bisphenol A, and the like.

  Examples of the diol component (B) other than the glycol (b1) having a hydrocarbon group in the side chain include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 1,7-heptanediol 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol F, water Bisphenol F, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, polyoxypropylene polyoxytetramethylene glycol or polyoxyethylene polyoxypropylene polyoxytetramethylene glycol And the like.

  The polyester [I] of the present invention is obtained by subjecting the dicarboxylic acid component (A) and the diol component (B) to a polycondensation reaction by a known method in the presence of a catalyst. Usually, esterification is performed by dehydration and / or dealcoholization reaction at a temperature of 150 ° C. to 260 ° C. The molecular weight is adjusted by adjusting the charging ratio between the dicarboxylic acid component (A) and the diol component (B). Usually, the OH functional group in the diol component (B) is charged in excess with respect to 1 mol of the COOH functional group in the dicarboxylic acid component (A) (the COOH functional group of one acid anhydride group is 2 mol). It is preferable to charge at a ratio of OH / COOH = 1/1 to 1.50 / 1, more preferably at a ratio of 1.05 / 1 to 1.30 / 1. The closer to 1/1, the higher the molecular weight, and the closer to 1.50 / 1, the lower the molecular weight. In order to further increase the molecular weight, the dediol reaction may be carried out under a reduced pressure of 5 mmHg or less.

  A catalyst is preferably used for the dediol reaction. For example, titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based compounds such as antimony trioxide, germanium-based catalysts such as germanium oxide, zinc acetate, manganese acetate, dibutyltin oxide, etc. 1 type (s) or 2 or more types are used. Among these, antimony trioxide and tetrabutyl titanate are preferable from the viewpoint of high catalyst activity.

  The weight average molecular weight (Mw) of the polyester [I] of the present invention is preferably in the range of 30000 to 300000 from the viewpoint of adhesiveness, and more preferably in the range of 50000 to 200000. If the Mw is less than 30000, the cohesive force cannot be expressed, and the heat resistance and moist heat resistance are reduced. On the other hand, if Mw exceeds 300,000, the fluidity of the resin becomes poor, and it becomes difficult to produce a resin laminate.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyester [I] of the present invention is preferably 1.5 to 5.0, more preferably 2.0 to 4.0. preferable. When Mw / Mn is less than 1.5, the heat resistance and heat-and-moisture resistance are inferior, and when used for laminating optical members, problems such as film peeling and white spots may occur. On the other hand, if it exceeds 5.0, the viscosity may be increased to cause a problem in handling.

  The polyester [I] of the present invention has a glass transition temperature of −80 to 0 ° C. When the glass transition temperature is less than −80 ° C., the cohesive force of the pressure-sensitive adhesive layer obtained by using the polyester may be reduced, and floating may occur. On the other hand, when the glass transition temperature exceeds 0 ° C., the pressure-sensitive adhesive layer may not exhibit sufficient tack. In addition, a glass transition temperature can be measured using DSC (differential thermothermogravimetry).

  The hydroxyl value of the polyester [I] of the present invention is preferably 0.1 to 30 mgKOH / g, and more preferably 2 to 20 mgKOH / g. If it is less than 0.1 mgKOH / g, the cohesive strength may be reduced, and if it is more than 30 mgKOH / g, the amount of adhesion and heat-and-moisture resistance may be reduced.

  Next, the branched polyester [II] of the present invention will be described. Polyester [II] is a diol containing a dicarboxylic acid component (A) containing an aromatic dicarboxylic acid (a1) and a glycol (b1) having a hydrocarbon group in the side chain, as in the case of the linear polyester [I]. Although it is a polyester obtained by polycondensation with the component (B), a trihydric or higher polyhydric alcohol (c1) and / or a trihydric or higher polyhydric carboxylic acid (c2) is an essential component. That is, it is a polyester having a branched structure.

  By using the aromatic dicarboxylic acid (a1), the heat resistance and heat-and-moisture resistance are improved, and problems such as film peeling and white spots do not occur when used for laminating optical members. In this invention, it is preferable to use 10-80 mol% in an aromatic dicarboxylic acid type | system | group (a1) in a dicarboxylic acid component (A) as dicarboxylic acid component (A), and it is further using 20-70 mol%. preferable. When the amount of the aromatic dicarboxylic acid (a1) used is less than 10 mol%, the heat resistance and heat-and-moisture resistance are inferior, and when used for laminating optical members, problems such as film peeling and white spots may occur. Moreover, when it exceeds 80 mol%, adhesiveness falls and sufficient adhesive force may not be acquired.

  As the aromatic dicarboxylic acid type (a1) of the present invention, those similar to those exemplified for the polyester [I] can be used. Among these, terephthalic acid and isophthalic acid are preferable from the viewpoint of heat resistance and wet heat resistance.

  As the dicarboxylic acid component (A) other than the aromatic dicarboxylic acid (a1), those similar to the polyester [I] can be used.

  In addition, polyester [II] uses glycol (b1) having a hydrocarbon group in the side chain to improve the wettability with respect to the substrate, improve heat resistance and moist heat resistance, and is used for laminating optical members. In this case, problems such as film peeling and white spots do not occur. In this invention, it is preferable to use 10-70 mol% of glycol (b1) which has a hydrocarbon group in a side chain as a diol component (B), and it is still more preferable to use 20-60 mol%. If the amount of glycol (b1) having a hydrocarbon group in the side chain is less than 10 mol%, the heat resistance and heat-and-moisture resistance are inferior, and problems such as film peeling and white spots occur when used for laminating optical members. There is a case. Moreover, when it exceeds 70 mol%, it exists in the tendency for a tack to fall, polymerization time becomes long, and a problem may be produced in productivity.

  As the glycol (b1) having a hydrocarbon group in the side chain, the same ones as exemplified for the polyester [I] can be used. In addition, as the diol component (B) other than the glycol (b1) having a hydrocarbon group in the side chain, those similar to those exemplified for the polyester [I] can be used.

  Polyester [II] of the present invention is a polycondensation of a trihydric or higher polyhydric alcohol (c1) and / or a trihydric or higher polyhydric carboxylic acid (c2) together with a dicarboxylic acid component (A) and a diol component (B). It is characterized by becoming. That is, 1 mol% to the total of the dicarboxylic acid component (A), the diol component (B), the trivalent or higher polyhydric alcohol (c1), and the trivalent or higher polyvalent carboxylic acid (c2). Polycondensation of 20 mol% of trihydric or higher polyhydric alcohol (c1) and / or trihydric or higher polyhydric carboxylic acid (c2) together with dicarboxylic acid component (A) and diol component (B) It is characterized by. When the trihydric or higher polyhydric alcohol (c1) and / or the trihydric or higher polyhydric carboxylic acid (c2) is less than 1 mol%, the number of reactive functional groups decreases and the cohesive force decreases. As a result, the heat resistance and heat-and-moisture resistance are poor, and problems such as peeling and white spots occur in optical applications. Moreover, when it exceeds 20 mol%, it will be easy to raise | generate gelation and a synthesis | combination will become difficult.

  Examples of the trihydric or higher polyhydric alcohol (c1) include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2, Examples include 6-hexanetriol.

  Examples of the trivalent or higher polyvalent carboxylic acid (c2) include aliphatic polyvalent carboxylic acids and aromatic polyvalent carboxylic acids. Examples of the aliphatic polycarboxylic acid include 3-carboxymethyl glutaric acid, 1,2,4-butanetricarboxylic acid, cis-propene-1,2,3-tricarboxylic acid, and 1,3,4-cyclopentanetricarboxylic acid. Acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid, 1,2 , 3,4-cyclopentanetetracarboxylic acid, 2,3,5-tricarboxycyclopentylacetic acid, 3,5,6-tricarboxynorbornane-2-acetic acid, 2,3,4,5-tetrahydrofurantetracarboxylic acid, 5 -(2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, bicyclo [2,2,2] -oct 7-ene-2,3,5,6-tetracarboxylic acid and the like.

  Examples of the aromatic polycarboxylic acid include 1,2,3-benzenetricarboxylic acid, trimellitic acid, 1,2,4-naphthalenetricarboxylic acid, 1,4,5-naphthalenetricarboxylic acid, and 2,3. , 6-Naphthalenetricarboxylic acid, 1,2,8-naphthalenetricarboxylic acid, 3,4,4′-benzophenone tricarboxylic acid, 3,4,4′-biphenyl ether tricarboxylic acid, 3,4,4′-biphenyltricarboxylic acid 2,3,2′-biphenyltricarboxylic acid, 3,4,4′-biphenylmethanetricarboxylic acid, 3,4,4′-biphenylsulfonetricarboxylic acid, pyromellitic acid, 3,3 ′, 4,4′- Benzophenone tetracarboxylic acid, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic acid, 1,4,5,8-naphthalene tet Carboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic acid, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic acid, 3 , 3 ′, 4,4′-tetraphenylsilanetetracarboxylic acid, 1,2,3,4-furantetracarboxylic acid, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide, 4,4 '-Bis (3,4-dicarboxyphenoxy) diphenylsulfone, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylpropane, 3,3', 4,4'-perfluoroisopropylidene diphthalic acid 3,3 ′, 4,4′-biphenyltetracarboxylic acid, bis (phthalic acid) phenylphosphine oxide, p-phenylene-bis (triphenyl) Phthalic acid), m-phenylene-bis (triphenylphthalic acid), bis (triphenylphthalic acid) -4,4'-diphenyl ether, bis (triphenylphthalic acid) -4,4'-diphenylmethane, 9,9- Bis (3,4-dicarboxyphenyl) fluorenic acid, 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic acid, 3,4-dicarboxy-1,2,3,4- Examples include tetrahydro-1-naphthalene succinic acid and 3,4-dicarboxy-1,2,3,4-tetrahydro-6-methyl-1-naphthalene succinic acid.

  Furthermore, as the polyvalent carboxylic acid (c2) having a valence of 3 or more, an anhydride of the polyvalent carboxylic acid can also be used.

  Like the polyester [I], the polyester [II] of the present invention comprises a dicarboxylic acid component (A), a diol component (B), a trihydric or higher polyhydric alcohol (c1) and / or a trivalent or higher polyvalent. It can be obtained by subjecting the polyvalent carboxylic acid (c2) to a polycondensation reaction by a known method. The diol component (B) and the dicarboxylic acid component (A) and the trivalent or higher polyvalent carboxylic acid (c2) with respect to 1 mole of COOH functional groups (2 moles of COOH functional group of one acid anhydride group) An excessive amount of OH functional groups in the trihydric or higher polyhydric alcohol (c1) is charged. It is preferable to charge at a ratio of OH / COOH = 1/1 to 2/1, more preferably 1.1 / 1 to 1.8 / 1, and a ratio of 1.1 / 1 to 1.5 / 1. It is particularly preferable to charge. The closer to 1/1, the higher the molecular weight resin, and the closer to 2/1, the lower the molecular weight resin.

  The weight average molecular weight (Mw) of the polyester [II] of the present invention is preferably in the range of 3000 to 100,000, and more preferably in the range of 5,000 to 50,000 in terms of cohesive strength and degree of crosslinking. When Mw is less than 3000, the heat resistance and the heat and humidity resistance are lowered. On the other hand, when Mw exceeds 100,000, the fluidity of the resin becomes poor and there is a risk of gelation.

  The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyester [II] of the present invention is preferably 2.0 to 8.0, more preferably 3.0 to 6.0. preferable. When Mw / Mn is less than 2.0, the heat resistance and heat-and-moisture resistance are inferior, and when used for laminating optical members, problems such as film peeling and white spots may occur. On the other hand, if it exceeds 8.0, the viscosity may be increased to cause a problem in handling.

  The polyester [II] of the present invention preferably has a glass transition temperature of −70 to 10 ° C. When the glass transition temperature is less than −70 ° C., the cohesive force of the pressure-sensitive adhesive layer obtained using the polyester may be reduced, and floating may occur. On the other hand, when the glass transition temperature exceeds 10 ° C., the pressure-sensitive adhesive layer may not exhibit sufficient tack.

  The hydroxyl value of the polyester [II] of the present invention is preferably 1 to 100 mgKOH / g, and more preferably 5 to 80 mgKOH / g. When the amount is less than 1 mgKOH / g, the crosslinking may not be sufficiently performed and the cohesive force may decrease, and when the amount exceeds 100 mgKOH / g, the adhesive force may decrease.

  The pressure-sensitive adhesive composition of the present invention is characterized by containing polyester [I] and polyester [II]. Polyester [I] is a straight-chain high molecular weight polyester having no branch, and exhibits high cohesion and stress relaxation. Polyester [II] is a highly branched polyester that contributes to the crosslinking reaction and improves heat resistance and heat-and-moisture resistance. The blending ratio of each polyester is a weight ratio, and polyester [I]: polyester [II] = 50: 50 to 99: 1 is preferable, and 60:40 to 90:10 is more preferable. If the amount of polyester [I] is less than the above range, tack and stress relaxation tend to be insufficient, and if the amount of polyester [II] is small, the crosslinking reaction tends to be insufficient, and the heat resistance and heat-and-moisture resistance tend to decrease.

  In addition, the total of the constituent components of each aromatic dicarboxylic acid (a1) is 10 to 80 mol% as the dicarboxylic acid component (A) in the total of polyester [I] and polyester [II]. Preferably, it is used in an amount of 20 to 70 mol%. Further, as the diol component (B), the total of the constituent components of the glycol (b1) having a hydrocarbon group in the side chain is preferably 10 to 70 mol%, and more preferably 20 to 60 mol%.

  The pressure-sensitive adhesive composition of the present invention contains the polyester [I], the polyester [II], and a compound (D) having a functional group capable of reacting with a reactive functional group in the polyester as a crosslinking agent. It is characterized by doing. Examples of the reactive functional group in the polyester include a hydroxyl group and a carboxyl group. Therefore, as a functional group which the compound (D) used for this invention has, an isocyanate group, an epoxy group, an alkoxysilyl group, a methylol group, etc. are mentioned. Examples of the compound (D) include a polyisocyanate compound, a polyfunctional silane compound, an N-methylol group-containing compound, etc. Among these, in order to act as a crosslinking agent, it can react with a hydroxyl group in the polyester. A compound having two or more functional groups in the molecule is preferably used. In particular, polyisocyanate compounds and polyfunctional silane compounds are preferably used because they are excellent in the adhesion of the resin composition after the crosslinking reaction and the adhesion to the coating layer.

  Examples of the polyisocyanate compound include aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, and alicyclic polyisocyanate.

  Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6 -Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', Examples thereof include 4 "-triphenylmethane triisocyanate.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, and dodeca. Examples include methylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate.

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene. 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, Examples thereof include methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane and the like.

  Moreover, the trimethylol propane adduct body of the said polyisocyanate, the trimer which has an isocyanurate ring, etc. can be used. Furthermore, polyphenylmethane polyisocyanate (PAPI), naphthylene diisocyanate, and these polyisocyanate modified products can be used. As the polyisocyanate-modified product, a carbodiimide group, a uretdione group, a uretoimine group, a burette group reacted with water, a group selected from isocyanurate groups, or a modified product having two or more of these groups can be used. . A reaction product of polyol and diisocyanate can also be used as polyisocyanate.

  Among these polyisocyanate compounds, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (also known as isophorone diisocyanate), xylylene diisocyanate, 4,4 ′ Use of a non-yellowing or hard-yellowing polyisocyanate compound such as methylenebis (cyclohexyl isocyanate) (also known as hydrogenated MDI) is particularly preferred from the viewpoint of weather resistance, heat resistance, and moist heat resistance.

  When a polyisocyanate compound is used as the compound (D), a known catalyst can be used as necessary to accelerate the reaction. For example, a tertiary amine compound, an organometallic compound, etc. are mentioned, and it is possible to use a single compound or plural compounds.

Examples of the polyfunctional silane compound include a silane coupling agent. Examples of the silane coupling agent include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropyl. A silane compound having two methacryloxy groups such as methyldiethoxysilane, an alkyl group and an alkoxy group;
a silane compound having two acryloxy groups, an alkyl group and an alkoxy group, such as γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, and γ-acryloxypropylmethyldimethoxysilane;
Silane compounds having three (meth) acryloxyalkyl groups and three alkoxy groups such as γ-methacryloxymethyltrimethoxysilane and γ-acryloxymethyltrimethoxysilane;
Alkoxysilanes having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane;
Alkoxysilanes having an alkyl group such as 5-hexenyltrimethoxysilane, 9-decenyltrimethoxysilane, styryltrimethoxysilane;
Silanes having aminoalkyl groups and alkoxy groups such as γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane;
Tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane;
3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane , Phenyltrimethoxysilane, hexamethylsilazane, diphenyldimethoxysilane, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl)- Examples include 3-aminopropylmethyldimethoxysilane and N- (2-aminoethyl) -3-aminopropyltrimethoxysilane.

  The pressure-sensitive adhesive composition of the present invention preferably contains 0.001 to 20 parts by weight of the compound (D) with respect to 100 parts by weight of the total of the polyester [I] and the polyester [II]. It is more preferable to contain 01-10 weight part. When the amount of the compound (D) used exceeds 20 parts by weight, the pressure-sensitive adhesive layer has a dense cross-linking structure when formed from a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive layer tends to have a reduced tack. The adhesiveness to the adherend is lowered or the stress relaxation property is lowered, which tends to cause heat unevenness. On the other hand, when the amount is less than 0.001 part by weight, a sufficient cross-linked structure cannot be obtained, and the cohesive force tends to decrease, and the heat resistance and heat-and-moisture resistance tend to decrease. The reaction between the reactive functional group in the polyester and the functional group in the compound (D) causes the resin composition to be three-dimensionally cross-linked, not only ensuring adhesion to various substrates and adherends, but also from the past. However, since the heat resistance and heat-and-moisture resistance under severe conditions can also be improved, it can be preferably used for an optical member.

  In the pressure-sensitive adhesive composition of the present invention, various resins, coupling agents, softeners, dyes, pigments, antioxidants, ultraviolet absorbers, weathering stabilizers, as long as the effects of the present invention are not impaired. , Tackifier, plasticizer, filler, anti-aging agent and the like may be blended.

  Using the pressure-sensitive adhesive composition of the present invention, a laminated product (hereinafter referred to as “adhesive sheet”) composed of a pressure-sensitive adhesive layer and a sheet-like substrate can be obtained. For example, a pressure-sensitive adhesive sheet can be obtained by coating, drying and curing the pressure-sensitive adhesive composition of the present invention on various sheet-like substrates. Since the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet is “pressure-sensitive”, it has tack at about room temperature. When applying the pressure-sensitive adhesive composition, an appropriate liquid medium, for example, an organic solvent such as ethyl acetate, toluene, methyl ethyl ketone, isopropyl alcohol, other hydrocarbon solvents, or water is further added to increase the viscosity. It can also be adjusted, and the pressure-sensitive adhesive composition can be heated to lower the viscosity. However, care should be taken because adding water or alcohol in a large amount may cause reaction inhibition between the polyester and the compound (D).

  Examples of the sheet-like base material include cellophane, various plastic sheets, rubber, foam, cloth, rubber cloth, resin-impregnated cloth, glass plate, metal plate, wood and the like in a flat shape. Various base materials can be used alone or in a multi-layered state in which a plurality of base materials are laminated. Further, the surface can be peeled off.

  Various plastic sheets are also called various plastic films, such as polyvinyl alcohol film, triacetyl cellulose film, polypropylene, polyethylene, polycycloolefin, polyolefin resin film such as ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate. , Polyester resin film such as polyethylene naphthalate, Polycarbonate resin film, Polynorbornene resin film, Polyarylate resin film, Acrylic resin film, Polyphenylene sulfide resin film, Polystyrene resin film, Vinyl Resin film, polyamide resin film, polyimide resin film, epoxy resin film, etc. It is below.

  When the pressure-sensitive adhesive composition contains a liquid medium such as an organic solvent or water after the pressure-sensitive adhesive composition is applied to the sheet-like base material by an appropriate method according to a conventional method, the liquid medium If the pressure-sensitive adhesive composition does not contain a liquid medium to be volatilized, the adhesive layer in the molten state is cooled and solidified, and the adhesive layer is formed on the sheet-like substrate. Can be formed. The thickness of the pressure-sensitive adhesive layer is preferably 0.1 μm to 200 μm, and more preferably 1 μm to 100 μm. If the thickness is less than 0.1 μm, sufficient adhesive strength may not be obtained, and if it exceeds 200 μm, characteristics such as adhesive strength are often not improved further.

  The method for applying the pressure-sensitive adhesive composition of the present invention to a sheet-like substrate is not particularly limited, and may be a Meyer bar, applicator, brush, spray, roller, gravure coater, die coater, lip coater, comma coater, Various coating methods such as a knife coater, a reverse coater, and a spin coater can be used. There is no particular limitation on the drying method, and examples include those using hot air drying, infrared rays or a reduced pressure method. As drying conditions, although it depends on the cured form of the adhesive composition, the film thickness, and the selected solvent, heating with hot air at about 60 to 180 ° C. is usually sufficient.

  The laminate of the present invention has various optical properties such as a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, and a brightness enhancement film, so-called sheet (also referred to as a film as described above) in an optical member, The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention is laminated. On the other surface of the pressure-sensitive adhesive layer, a sheet-like base material subjected to a release treatment can be laminated.

The laminate of the present invention is
(A) A pressure-sensitive adhesive composition is applied to the release-treated surface of the release-treated sheet-like substrate, dried, and a sheet-like optical member is laminated on the surface of the pressure-sensitive adhesive layer,
(A) A pressure-sensitive adhesive composition is applied to a sheet-like optical member, dried, and the release-treated surface of the peeled sheet-like substrate is laminated on the surface of the pressure-sensitive adhesive layer. be able to.

  By peeling off the release-treated sheet-like substrate covering the surface of the pressure-sensitive adhesive layer from the laminate thus obtained, for example, by sticking the pressure-sensitive adhesive layer to the glass member for liquid crystal cells A liquid crystal cell member having a configuration of “sheet-like optical member / pressure-sensitive adhesive layer / glass member for liquid crystal cell” can be obtained.

  Since the pressure-sensitive adhesive composition of the present invention is composed of polyester, it has improved adhesion to a substrate, is excellent in plasticizer resistance and low-temperature adhesion, and is suitable for a substrate such as a foam. It is also suitably used for applications that require adhesion. In particular, since an aromatic ring can be contained in the main chain skeleton, the refractive index after drying and / or curing of the pressure-sensitive adhesive composition can be maintained at 1.45 or more. As described above, the refractive index of the material used for the optical member such as the optical member film or glass is about 1.50 to 1.58, and the pressure-sensitive adhesive composition is dried and dried. If the refractive index after curing is less than 1.45, the difference in refractive index between the optical film and the optical member increases. Therefore, for example, when an adhesive layer obtained from the pressure-sensitive adhesive composition is provided on a film light guide plate which is a kind of optical film, total reflection occurs at a shallow angle, and effective use of light is achieved. May decrease. Moreover, in order to reduce the refractive index difference from the optical film or optical member, the refractive index after drying and / or curing of the pressure-sensitive adhesive composition of the present invention is controlled in the range of 1.49 to 1.60. What you can do is also important. In particular, control is possible in the range of 1.50 to 1.55.

  EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise specified.

(Synthesis Example 1) “Synthesis of linear polyester [I]”
A dicarboxylic acid component (A) and a diol component (B) were respectively charged in the following ratios in a polymerization tank of a polymerization reactor equipped with a stirrer, a thermometer, a water separator, a reflux condenser, and a nitrogen introduction tube. .

[Polymerization tank]
Isophthalic acid 88.24 parts Adipic acid 155.22 parts Sebacic acid 214.76 parts Ethylene glycol 54.38 parts 1,4-Butanediol 52.63 parts 1,6-Hexanediol 69.00 parts 2-Butyl-2- Ethyl-1,3-propanediol 70.17 parts Neopentyl glycol 45.61 parts

  After the air in the polymerization tank was replaced with nitrogen gas, the temperature was raised to 160 ° C. in a nitrogen atmosphere while stirring. After confirming dehydration at 160 ° C., the temperature was raised by 10 ° C. every 30 minutes, and the temperature was raised to 250 ° C. to conduct a dehydration reaction. The reaction was further continued at 250 ° C, and when the acid value became 15 mgKOH / g or less, the temperature was lowered to 150 ° C. At 150 ° C., 0.1 part of tetrabutyl titanate was added, the temperature was raised to 240 ° C., and when the temperature reached 240 ° C., the pressure was gradually reduced, and a dediol reaction was carried out at 5 mmHg or less for 5 hours. The reaction was terminated after confirming that the molecular weight was reached. This polyester was dissolved in a methyl ethyl ketone / ethyl acetate mixed solution (weight ratio = 1/1) and adjusted to a solid content of 50% to obtain a polyester solution (A-1). The characteristic values of the obtained resin solution are shown in Table-1.

(Synthesis Examples 2 and 3) "Synthesis of linear polyester [I]"
Synthesis was performed in the same manner as in Synthesis Example 1 according to the charged composition shown in Table 1, and polyester solutions (A-2, A-3) were obtained. The characteristic values of the obtained resin solution are shown in Table-1.

(Synthesis Example 4) “Synthesis of linear polyester [I]”
A dicarboxylic acid component (A) and a diol component (B) were respectively charged in the following ratios in a polymerization tank of a polymerization reactor equipped with a stirrer, a thermometer, a water separator, a reflux condenser, and a nitrogen introduction tube. .

[Polymerization tank]
Dimethylterephthalic acid 233.65 parts Ethylene glycol 32.86 parts 1,4-butanediol 35.77 parts 1,6-hexanediol 46.90 parts 2-butyl-2-ethyl-1,3-propanediol 105.99 Parts Neopentyl glycol 68.89 parts Zinc acetate (catalyst) 0.035 parts

  After the air in the polymerization tank was replaced with nitrogen gas, the temperature was raised to 160 ° C. in a nitrogen atmosphere while stirring. After confirming the removal of methanol at 160 ° C., the temperature was raised by 10 ° C. every 30 minutes, the temperature was raised to 210 ° C. to carry out the demethanol reaction, and the reaction was continued until the distillation of methanol stopped. When the methanol removal reaction was completed, the temperature was lowered to 150 ° C. At 150 ° C., 79.97 parts of isophthalic acid and 145.97 parts of sebacic acid were added, the temperature was raised, and the temperature was raised to 250 ° C. for dehydration reaction. The reaction was terminated when the acid value became 15 mgKOH / g or less, and the temperature was lowered to 150 ° C. Next, 0.1 part of tetrabutyl titanate was added, the temperature was raised to 240 ° C., and when the temperature reached 240 ° C., the pressure was gradually reduced, and a dediol reaction was performed at 5 mmHg or less for 5 hours. The reaction was terminated after confirming that the molecular weight was reached. This polyester was dissolved in a methyl ethyl ketone / ethyl acetate mixed solution (weight ratio = 1/1) and adjusted to a solid content of 50% to obtain a polyester solution (A-4). The characteristic values of the obtained resin solution are shown in Table-1.

(Synthesis Example 5) “Synthesis of Linear Polyester (Comparative Synthesis Example)”
Synthesis was performed in the same manner as in Synthesis Example 1 in accordance with the charged composition shown in Table 1 to obtain a polyester solution (A-5). The characteristic values of the obtained resin solution are shown in Table-1.

Synthesis Example 6 “Synthesis of Branched Polyester [II]”
In a polymerization tank of a polymerization reactor equipped with a stirrer, a thermometer, a water separator, a reflux condenser, and a nitrogen introduction tube, a dicarboxylic acid component (A), a diol component (B), and a trihydric or higher polyhydric alcohol ( c1) was charged at the following ratios.

[Polymerization tank]
Isophthalic acid 86.84 parts Adipic acid 152.75 parts Sebacic acid 211.34 parts 1,4-Butanediol 33.66 parts 1,6-Hexanediol 44.14 parts 2-Butyl-2-ethyl-1,3- Propanediol 59.84 parts Neopentyl glycol 32.91 parts Trimethylolpropane 128.51 parts

  After the air in the polymerization tank was replaced with nitrogen gas, the temperature was raised to 160 ° C. in a nitrogen atmosphere while stirring. After confirming dehydration at 160 ° C., the temperature was raised by 10 ° C. every 30 minutes, and the temperature was raised to 240 ° C. to conduct dehydration reaction. The reaction was further continued at 240 ° C., and the reaction was terminated when the acid value reached a predetermined value. Thereafter, unreacted monomers were distilled off for 30 minutes under a reduced pressure of 100 mmHg, and then this polyester was dissolved in a methyl ethyl ketone / ethyl acetate mixed solution (weight ratio = 1/1) and adjusted to a solid content of 50%. A solution (A-6) was obtained. The characteristic values of the obtained resin solution are shown in Table 2.

(Synthesis Examples 7 to 10 and 12) "Synthesis of branched polyester [II]"
Synthesis was performed in the same manner as in Synthesis Example 5 according to the charging composition shown in Table 2, and polyester solutions (A-7) to (A-10) and (A-12) were obtained. The characteristic values of the obtained resin solution are shown in Table 2.

(Synthesis Example 11) “Synthesis of Branched Polyester (Comparative Synthesis Example)”
Synthesis was performed in the same manner as in Synthesis Example 5 in accordance with the charged composition shown in Table 2, to obtain a polyester solution (A-11). The characteristic values of the obtained resin solution are shown in Table 2.

(Synthesis Example 13) “Synthesis of Acrylic Resin (Comparative Synthesis Example)”
In a four-necked separable flask equipped with a thermometer, stirrer, distillation tube, condenser, and dropping funnel, 49 g of 2-ethylhexyl acrylate, 50 g of phenoxyethyl acrylate, 1 g of acrylic acid and 2,2′-azobisisobutyronitrile 0 .2 g was added with 100 g of toluene and refluxed with nitrogen at room temperature for 1 hour, and then the temperature was raised to 60 ° C. for 4 hours under the nitrogen stream, followed by reaction for 4 hours and then aged for 2 hours by raising the temperature to 80 ° C. Thus, an acrylic resin solution (A-13) was obtained. The obtained acrylic resin had a weight average molecular weight of 59,000, a dispersity of 5.8, an acid value of 7.8 mgKOH / g, and a glass transition temperature of −35.3 ° C.

  The weight average molecular weight (Mw), dispersity, acid value, and glass transition temperature (Tg) of each resin obtained in Synthesis Examples 1 to 13 were determined according to the following methods, and the results are shown in Tables 1 and 2. .

<Measurement of weight average molecular weight (Mw)>
For measurement of Mw, GPC (gel permeation chromatography) “HPC-8020” manufactured by Tosoh Corporation was used. GPC is liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified by the difference in molecular size, and the weight average molecular weight (Mw) is determined in terms of polystyrene.

<Dispersity>
The weight average molecular weight (Mw) determined by GPC was divided by the number average molecular weight (Mn) determined in the same manner to obtain the dispersity.

<Acid value>
2 g of the resin solution synthesized in Synthesis Examples 1 to 13 was dissolved in 30 ml of a mixed solvent of toluene / isopropyl alcohol = 70/30 (weight ratio) and titrated with a 0.1 mol / L KOH ethanol solution to obtain 1 g of resin solid content. The number of mg of KOH per unit was determined.

<Measurement of glass transition temperature (Tg)>
The measurement was performed by connecting a “SSC5200 disk station” (manufactured by Seiko Instruments Inc.) to a robot DSC (differential scanning calorimeter) “RDC220” (manufactured by Seiko Instruments Inc.). About 10 mg of sample was weighed in an aluminum pan and set in a DSC apparatus (reference: the same type of aluminum pan without sample). After heating at 300 ° C. for 5 minutes, using liquid nitrogen − Rapid cooling was performed to 120 ° C. Thereafter, the temperature was raised at 10 ° C./min, and the glass transition temperature (Tg) was calculated from the obtained DSC chart (unit: ° C.).

Example 1
About 25 parts of toluene was added to 60 parts (solid content 50%) of the polyester solution (A-1) obtained in Synthesis Example 1 and 40 parts (solid content 50%) of the polyester solution (A-8). % Was adjusted. Next, 2.5 parts of TDI / TMP (tolylene diisocyanate trimethylolpropane adduct) as the curing agent (D) and 3-glycidoxypropyltrimethoxysilane as the silane coupling agent 0.5 part was added and stirred well to obtain a pressure-sensitive adhesive composition of the present invention.

  This was coated on a release-treated polyester film (hereinafter referred to as “release film”) so that the thickness after drying was 25 μm, and dried at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer. . After drying, one side of a polarizing film with a three-layer structure in which both sides of a polyvinyl alcohol (PVA) polarizer are sandwiched between triacetyl cellulose protective films (hereinafter referred to as “TAC film”) is bonded to the pressure-sensitive adhesive layer. A laminate having a configuration of “release film / pressure-sensitive adhesive layer / TAC film / PVA / TAC film” was obtained. Next, the obtained laminate was aged (dark reaction) for one week under the condition of a temperature of 23 ° C. and a relative humidity of 50%, and the reaction of the adhesive layer was advanced to produce a bonded polarizing plate (laminate).

(Examples 2 to 6)
Polyester [I] and polyester [II] were mixed according to the combinations in Table 3, and a pressure-sensitive adhesive composition was produced in the same manner as in Example 1. A polarizing plate (laminated body) bonded with the obtained pressure-sensitive adhesive composition was produced.

(Comparative Example 1)
About 25 parts of toluene was added to 100 parts (solid content 50%) of the polyester solution (A-3) obtained in Synthesis Example 3 to adjust the solid content to 40%. Next, 2.5 parts of TDI / TMP (tolylene diisocyanate trimethylolpropane adduct) as the curing agent (D) and 3-glycidoxypropyltrimethoxysilane as the silane coupling agent 0.5 part was added and stirred well to obtain a pressure-sensitive adhesive composition.

(Comparative Example 2)
About 25 parts of toluene was added to 60 parts (solid content 50%) of the polyester solution (A-5) obtained in Synthesis Example 5 and 40 parts (solid content 50%) of the polyester solution (A-8) obtained in Synthesis Example 8. The solid content was adjusted to 40%. Next, 2.5 parts of TDI / TMP (trimethylolpropane adduct of tolylene diisocyanate) was added as the curing agent (D) and stirred well to obtain a pressure-sensitive adhesive composition.

(Comparative Example 3)
About 25 parts of toluene was added to 100 parts (solid content 50%) of the polyester solution (A-11) obtained in Synthesis Example 11 to adjust the solid content to 40%. Next, 2.5 parts of TDI / TMP (trimethylolpropane adduct of tolylene diisocyanate) was added as a curing agent (D) and stirred well, but the viscosity was too high and pressure sensitive adhesive composition I couldn't apply things.

(Comparative Example 4)
About 25 parts of toluene was added to 100 parts (solid content 50%) of the polyester solution (A-12) obtained in Synthesis Example 12 to adjust the solid content to 40%. Next, 2.5 parts of TDI / TMP (trimethylolpropane adduct of tolylene diisocyanate) was added as the curing agent (D) and stirred well to obtain a pressure-sensitive adhesive composition.

(Comparative Example 5)
About 25 parts of toluene was added to 100 parts (solid content 50%) of the polyester solution (A-12) obtained in Synthesis Example 12 to adjust the solid content to 40%. Subsequently, 5.0 parts of TDI / TMP (trimethylolpropane adduct of tolylene diisocyanate) as a curing agent (D) and 3-glycidoxypropyltrimethoxysilane as a silane coupling agent 0.5 part was added and stirred well to obtain a pressure-sensitive adhesive composition.

(Comparative Example 6)
About 25 parts of toluene was added to 100 parts (solid content 50%) of the acrylic resin solution (A-13) obtained in Synthesis Example 13 to adjust the solid content to 40%. Next, 2.5 parts of TDI / TMP (tolylene diisocyanate trimethylolpropane adduct) as the curing agent (D) and 3-glycidoxypropyltrimethoxysilane as the silane coupling agent 0.5 part was added and stirred well to obtain a pressure-sensitive adhesive composition.

(Comparative Example 7)
About 50 parts of the polyester solution (A-3) obtained in Synthesis Example 3 (solid content 50%) and 50 parts of the acrylic resin solution (A-13) obtained in Synthesis Example 13 (solid content 50%) were mixed with toluene. Although 25 parts were added and the solid content was adjusted to 40%, the polyester solution (A-3) and the acrylic resin solution (A-13) were poorly compatible and were clouded and separated, so evaluation could not be performed.

  About the adhesion-processed polarizing plate (laminate) obtained in Examples and Comparative Examples, the heat resistance, wet heat resistance, thermal unevenness, refractive index, and removability of the coating film were evaluated by the following methods. The results are shown in Table-3 and Table-4.

<Method for evaluating heat resistance and heat and humidity resistance>
The bonded polarizing plate (laminate) is cut into a size of 150 mm × 80 mm, the release film is peeled off, and the absorption axis of each polarizing plate is orthogonal to both surfaces of a 1.1 mm thick float glass plate. It stuck using the laminator. Subsequently, the glass plate on which the polarizing plate is attached is held in an autoclave at 50 ° C.-5 atm for 20 minutes to firmly adhere the polarizing plate to the glass plate, and the polarizing plate and the glass plate are laminated. I got a thing.

  As evaluation of heat resistance, the floating of the polarizing plate after leaving the laminate for 500 hours in an oven at 80 ° C., peeling, and deviation from the glass plate surface were visually evaluated. In addition, as evaluation of the heat and humidity resistance, the floating and peeling of the polarizing plate and the deviation from the glass plate surface after leaving the above laminate for 500 hours in a constant temperature and high humidity bath at 60 ° C. and 80% relative humidity were visually evaluated. The heat resistance and moist heat resistance were evaluated based on the following three-stage evaluation criteria.

○: “No floating, peeling or misalignment was observed, and there was no problem in practical use.”
Δ: “Slightly floating, peeling or misalignment is observed, but there is no practical problem”
×: “Floating over, peeling, misalignment, impractical”
Means each.

<Method for evaluating thermal unevenness>
The bonded polarizing plate (laminate) is cut into a size of 150 mm × 80 mm and the release film is peeled off so that the absorption axis of each polarizing plate is orthogonal to both surfaces of a 1.1 mm thick float glass plate. It stuck using the laminator. Subsequently, the glass plate on which the polarizing plate is attached is held in an autoclave at 50 ° C.-5 atm for 20 minutes to firmly adhere the polarizing plate to the glass plate, and the polarizing plate and the glass plate are laminated. I got a thing. After this laminate was left in an oven at 80 ° C. for 24 hours, light was applied from one side of the laminate, and light leakage of the polarizing plate was visually evaluated from the opposite side.

◯: The entire surface of the polarizing plate is uniform with a dark black hue.
Δ: The dark black color is thin within 10 mm at the four sides of the polarizing plate, but there is no practical problem.
X: Dark black is thinned to 10 mm or more at the four sides of the polarizing plate.

<Evaluation method of refractive index of coating film>
After the pressure-sensitive adhesive compositions obtained in Examples and Comparative Examples were coated on a release film and dried in an oven at 120 ° C. to provide a pressure-sensitive adhesive layer having a thickness of 25 μm, a polyester film A pressure-sensitive adhesive sheet was prepared by laminating and laminating. Thereafter, the Abbe refractometer “DR-M2” (manufactured by ATAGO) was irradiated with sodium D-line in an atmosphere at 25 ° C. to measure the refractive index of the adhesive layer on the adhesive sheet.

<Evaluation method of removability (reworkability)>
The bonded polarizing plate (laminated body) is cut into a size of 25 mm × 150 mm, the release film is peeled off, and is attached to a float glass plate with a thickness of 1.1 mm using a laminator. The polarizing plate was firmly adhered to the glass plate by holding it for 20 minutes. After leaving this test piece at 23 ° C. and 50% relative humidity for 1 week, a 180 ° peel test was performed in which the test piece was peeled off at a speed of 300 mm / min in the direction of 180 °, and the fogging of the glass surface after peeling was visually observed. Evaluation was made in three stages.

○: “No cloudiness, no problem in practical use”
Δ: “Slightly cloudy, but practically no problem”
X: “Transfer of the adhesive layer is recognized over the entire surface, which is impractical”
Means each.

  As described above, it can be seen that the pressure-sensitive adhesive composition of the present invention is excellent in heat resistance, moist heat resistance, heat unevenness, re-peelability, and refractive index controllability. In contrast, Comparative Example 1 is inferior in heat resistance and moist heat resistance, and Comparative Example 2 is inadequate in heat resistance and high refractive index and inferior in removability. In Comparative Example 3, the polyester resin solution was too viscous to be applied. Comparative Examples 4 and 5 cannot balance heat resistance / moisture heat resistance and heat unevenness due to the amount of the curing agent added. Comparative Example 6 had good heat resistance and moist heat resistance, but had poor heat unevenness. In Comparative Example 7, polyester was mixed with acrylic resin, but the compatibility was poor.

  Since the pressure-sensitive adhesive composition of the present invention can form a polymer in which an aromatic ring or an alicyclic ring is introduced into the main chain skeleton while maintaining the cohesive force peculiar to polyester, it cannot be obtained with an acrylic resin. Adhesive properties can be expressed. Examples thereof include heat resistance, moist heat resistance, optical characteristics, removability and the like in an optical laminate as in the present invention. In particular, in optical laminate applications, it is important that there is no light leakage, which is an optical property, and with the recent increase in size of displays, the required performance such as the control of refractive index has become increasingly severe. . Therefore, the pressure-sensitive adhesive composition of the present invention is considered to be more useful because it can exhibit properties that have been difficult so far as described above.

  The pressure-sensitive adhesive composition of the present invention is suitable for use as an optical member, and in addition to general labels and seals, paints, elastic wall materials, waterproof coating materials, flooring materials, tackifiers, adhesives, laminates Structural adhesives, sealing agents, molding materials, surface modification coating agents, binders (magnetic recording media, ink binders, casting binders, fired brick binders, graft materials, microcapsules, glass fiber sizing, etc.), urethane foam (Hard, semi-rigid, soft), urethane RIM, UV / EB curable resin, high solid paint, thermosetting elastomer, microcellular, fiber processing agent, plasticizer, sound absorbing material, vibration damping material, surfactant, gel coat agent Resin for artificial marble, impact modifier for artificial marble, resin for ink, film (laminate adhesive, protective film) Etc.), laminated glass resin, reactive diluent, various molding materials, elastic fiber, artificial leather, as a raw material for synthetic leather, can also very effectively used as various resin additives and a raw material thereof or the like.

Claims (6)

Weight average molecular weight 30000-300000 formed by polycondensation of dicarboxylic acid component (A) containing aromatic dicarboxylic acid (a1) and diol component (B) containing glycol (b1) having a hydrocarbon group in the side chain Polyester [I] and
A dicarboxylic acid component (A) containing an aromatic dicarboxylic acid (a1), a diol component (B) containing a glycol (b1) having a hydrocarbon group in the side chain, a trihydric or higher polyhydric alcohol (c1) and / or Or a polyester obtained by polycondensation with a trivalent or higher polyvalent carboxylic acid (c2), and a trivalent or higher polyhydric alcohol (c1) and / or a trivalent or higher polyvalent carboxylic acid (c2), 1 to 20 mol% of the total of the dicarboxylic acid component (A), the diol component (B), the trivalent or higher polyhydric alcohol (c1), and the trivalent or higher polyvalent carboxylic acid (c2) A pressure-sensitive adhesive composition comprising polyester [II] having a weight average molecular weight of 3000 to 100,000.   The pressure-sensitive adhesive composition according to claim 1, comprising a compound (D) having a functional group capable of reacting with a reactive functional group in the polyester [I] and / or the polyester [II].   The pressure-sensitive adhesive composition according to claim 2, wherein the compound (D) is a polyisocyanate compound.   The pressure-sensitive adhesive composition according to claim 3, further comprising a silane coupling agent.   The laminated body by which an optical member is laminated | stacked on the pressure sensitive adhesive layer formed from the pressure sensitive adhesive composition in any one of Claims 1-4.   A glass cell member for a liquid crystal cell, a pressure sensitive adhesive layer formed from the pressure sensitive adhesive composition according to any one of claims 1 to 4, and a member for a liquid crystal cell formed by sequentially laminating an optical member.